This invention relates generally to valves usable to deliver water from housing or building plumbing lines. More particularly, it concerns improvements to such valves, simplifying their construction, and enhancing their performance.
There is need in such valves for improvements associated with blocking or checking back flow where reverse flow pressure may build-up. Also, there is need in such valves for disposing of build-up back flow pressure, as during checking or blocking of such back flow to the building plumbing. Such back flow, if unchecked, could contaminate water in that plumbing.
U.S. Pat. No. 5,752,542 to Hoeptner discloses an improved valve constructed to meet the above needs. That valve incorporates the following:
a) an outer tubular member having a first flow port,
b) an inner member having closure means thereon to close the port in relatively axially advanced position of the inner member, and to open the port in relatively axially retracted position of the inner member,
c) control means to control relative movement of the inner member between those positions,
d) an axially movable check valve positioned about the axis of the inner member to pass fluid flow from the port and to drain flow space defined between the members, and to block reverse fluid flow from that space and through the first port, in the inner member relatively retracted position, and
e) a second port to pass fluid from that space in relatively retracted position of the inner member, thereby to relieve pressure of the fluid in the space.
There is further need to control pressurized fluid for escape from the interior of the valve at times when the check valve is positioned to block reverse fluid flow as referred to, and at other times to block such escape.